git.sesse.net Git - nageru/blob - alsa_pool.cpp

   1 #include "alsa_pool.h"
   2
   3 #include <alsa/asoundlib.h>
   4 #include <assert.h>
   5 #include <errno.h>
   6 #include <limits.h>
   7 #include <pthread.h>
   8 #include <poll.h>
   9 #include <stdint.h>
  10 #include <stdio.h>
  11 #include <sys/eventfd.h>
  12 #include <sys/inotify.h>
  13 #include <unistd.h>
  14 #include <algorithm>
  15 #include <chrono>
  16 #include <functional>
  17 #include <iterator>
  18 #include <memory>
  19 #include <ratio>
  20
  21 #include "alsa_input.h"
  22 #include "audio_mixer.h"
  23 #include "defs.h"
  24 #include "input_mapping.h"
  25 #include "state.pb.h"
  26
  27 using namespace std;
  28 using namespace std::placeholders;
  29
  30 ALSAPool::ALSAPool()
  31 {
  32         should_quit_fd = eventfd(/*initval=*/0, /*flags=*/0);
  33         assert(should_quit_fd != -1);
  34 }
  35
  36 ALSAPool::~ALSAPool()
  37 {
  38         for (Device &device : devices) {
  39                 if (device.input != nullptr) {
  40                         device.input->stop_capture_thread();
  41                 }
  42         }
  43         should_quit = true;
  44         const uint64_t one = 1;
  45         if (write(should_quit_fd, &one, sizeof(one)) != sizeof(one)) {
  46                 perror("write(should_quit_fd)");
  47                 exit(1);
  48         }
  49         inotify_thread.join();
  50
  51         while (retry_threads_running > 0) {
  52                 this_thread::sleep_for(std::chrono::milliseconds(100));
  53         }
  54 }
  55
  56 std::vector<ALSAPool::Device> ALSAPool::get_devices()
  57 {
  58         lock_guard<mutex> lock(mu);
  59         for (Device &device : devices) {
  60                 device.held = true;
  61         }
  62         return devices;
  63 }
  64
  65 void ALSAPool::hold_device(unsigned index)
  66 {
  67         lock_guard<mutex> lock(mu);
  68         assert(index < devices.size());
  69         devices[index].held = true;
  70 }
  71
  72 void ALSAPool::release_device(unsigned index)
  73 {
  74         lock_guard<mutex> lock(mu);
  75         if (index < devices.size()) {
  76                 devices[index].held = false;
  77         }
  78 }
  79
  80 void ALSAPool::enumerate_devices()
  81 {
  82         // Enumerate all cards.
  83         for (int card_index = -1; snd_card_next(&card_index) == 0 && card_index >= 0; ) {
  84                 char address[256];
  85                 snprintf(address, sizeof(address), "hw:%d", card_index);
  86
  87                 snd_ctl_t *ctl;
  88                 int err = snd_ctl_open(&ctl, address, 0);
  89                 if (err < 0) {
  90                         printf("%s: %s\n", address, snd_strerror(err));
  91                         continue;
  92                 }
  93                 unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
  94
  95                 // Enumerate all devices on this card.
  96                 for (int dev_index = -1; snd_ctl_pcm_next_device(ctl, &dev_index) == 0 && dev_index >= 0; ) {
  97                         probe_device_with_retry(card_index, dev_index);
  98                 }
  99         }
 100 }
 101
 102 void ALSAPool::probe_device_with_retry(unsigned card_index, unsigned dev_index)
 103 {
 104         char address[256];
 105         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 106
 107         lock_guard<mutex> lock(add_device_mutex);
 108         if (add_device_tries_left.count(address)) {
 109                 // Some thread is already busy retrying this,
 110                 // so just reset its count.
 111                 add_device_tries_left[address] = num_retries;
 112                 return;
 113         }
 114
 115         // Try (while still holding the lock) to add the device synchronously.
 116         ProbeResult result = probe_device_once(card_index, dev_index);
 117         if (result == ProbeResult::SUCCESS) {
 118                 return;
 119         } else if (result == ProbeResult::FAILURE) {
 120                 return;
 121         }
 122         assert(result == ProbeResult::DEFER);
 123
 124         // Add failed for whatever reason (probably just that the device
 125         // isn't up yet. Set up a count so that nobody else starts a thread,
 126         // then start it ourselves.
 127         fprintf(stderr, "Trying %s again in one second...\n", address);
 128         add_device_tries_left[address] = num_retries;
 129         ++retry_threads_running;
 130         thread(&ALSAPool::probe_device_retry_thread_func, this, card_index, dev_index).detach();
 131 }
 132
 133 void ALSAPool::probe_device_retry_thread_func(unsigned card_index, unsigned dev_index)
 134 {
 135         char address[256];
 136         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 137
 138         char thread_name[16];
 139         snprintf(thread_name, sizeof(thread_name), "Reprobe_hw:%d,%d", card_index, dev_index);
 140         pthread_setname_np(pthread_self(), thread_name);
 141
 142         for ( ;; ) {  // Termination condition within the loop.
 143                 sleep(1);
 144
 145                 // See if there are any retries left.
 146                 lock_guard<mutex> lock(add_device_mutex);
 147                 if (should_quit ||
 148                     !add_device_tries_left.count(address) ||
 149                     add_device_tries_left[address] == 0) {
 150                         add_device_tries_left.erase(address);
 151                         fprintf(stderr, "Giving up probe of %s.\n", address);
 152                         break;
 153                 }
 154
 155                 // Seemingly there were. Give it a try (we still hold the mutex).
 156                 ProbeResult result = probe_device_once(card_index, dev_index);
 157                 if (result == ProbeResult::SUCCESS) {
 158                         add_device_tries_left.erase(address);
 159                         fprintf(stderr, "Probe of %s succeeded.\n", address);
 160                         break;
 161                 } else if (result == ProbeResult::FAILURE || --add_device_tries_left[address] == 0) {
 162                         add_device_tries_left.erase(address);
 163                         fprintf(stderr, "Giving up probe of %s.\n", address);
 164                         break;
 165                 }
 166
 167                 // Failed again.
 168                 assert(result == ProbeResult::DEFER);
 169                 fprintf(stderr, "Trying %s again in one second (%d tries left)...\n",
 170                         address, add_device_tries_left[address]);
 171         }
 172
 173         --retry_threads_running;
 174 }
 175
 176 ALSAPool::ProbeResult ALSAPool::probe_device_once(unsigned card_index, unsigned dev_index)
 177 {
 178         char address[256];
 179         snprintf(address, sizeof(address), "hw:%d", card_index);
 180         snd_ctl_t *ctl;
 181         int err = snd_ctl_open(&ctl, address, 0);
 182         if (err < 0) {
 183                 printf("%s: %s\n", address, snd_strerror(err));
 184                 return ALSAPool::ProbeResult::DEFER;
 185         }
 186         unique_ptr<snd_ctl_t, decltype(snd_ctl_close)*> ctl_closer(ctl, snd_ctl_close);
 187
 188         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 189
 190         snd_pcm_info_t *pcm_info;
 191         snd_pcm_info_alloca(&pcm_info);
 192         snd_pcm_info_set_device(pcm_info, dev_index);
 193         snd_pcm_info_set_subdevice(pcm_info, 0);
 194         snd_pcm_info_set_stream(pcm_info, SND_PCM_STREAM_CAPTURE);
 195         err = snd_ctl_pcm_info(ctl, pcm_info);
 196         if (err == -ENOENT) {
 197                 // Not a capture card.
 198                 return ALSAPool::ProbeResult::FAILURE;
 199         }
 200         if (err < 0) {
 201                 // Not available for capture.
 202                 printf("%s: Not available for capture.\n", address);
 203                 return ALSAPool::ProbeResult::DEFER;
 204         }
 205
 206         unsigned num_channels = 0;
 207
 208         // Find all channel maps for this device, and pick out the one
 209         // with the most channels.
 210         snd_pcm_chmap_query_t **cmaps = snd_pcm_query_chmaps_from_hw(card_index, dev_index, 0, SND_PCM_STREAM_CAPTURE);
 211         if (cmaps != nullptr) {
 212                 for (snd_pcm_chmap_query_t **ptr = cmaps; *ptr; ++ptr) {
 213                         num_channels = max(num_channels, (*ptr)->map.channels);
 214                 }
 215                 snd_pcm_free_chmaps(cmaps);
 216         }
 217         if (num_channels == 0) {
 218                 // Device had no channel maps. We need to open it to query.
 219                 // TODO: Do this asynchronously.
 220                 snd_pcm_t *pcm_handle;
 221                 int err = snd_pcm_open(&pcm_handle, address, SND_PCM_STREAM_CAPTURE, 0);
 222                 if (err < 0) {
 223                         printf("%s: %s\n", address, snd_strerror(err));
 224                         return ALSAPool::ProbeResult::DEFER;
 225                 }
 226                 snd_pcm_hw_params_t *hw_params;
 227                 snd_pcm_hw_params_alloca(&hw_params);
 228                 unsigned sample_rate;
 229                 if (!ALSAInput::set_base_params(address, pcm_handle, hw_params, &sample_rate)) {
 230                         snd_pcm_close(pcm_handle);
 231                         return ALSAPool::ProbeResult::DEFER;
 232                 }
 233                 err = snd_pcm_hw_params_get_channels_max(hw_params, &num_channels);
 234                 if (err < 0) {
 235                         fprintf(stderr, "[%s] snd_pcm_hw_params_get_channels_max(): %s\n",
 236                                 address, snd_strerror(err));
 237                         snd_pcm_close(pcm_handle);
 238                         return ALSAPool::ProbeResult::DEFER;
 239                 }
 240                 snd_pcm_close(pcm_handle);
 241         }
 242
 243         if (num_channels == 0) {
 244                 printf("%s: No channel maps with channels\n", address);
 245                 return ALSAPool::ProbeResult::FAILURE;
 246         }
 247
 248         snd_ctl_card_info_t *card_info;
 249         snd_ctl_card_info_alloca(&card_info);
 250         snd_ctl_card_info(ctl, card_info);
 251
 252         string name = snd_ctl_card_info_get_name(card_info);
 253         string info = snd_pcm_info_get_name(pcm_info);
 254
 255         unsigned internal_dev_index;
 256         string display_name;
 257         {
 258                 lock_guard<mutex> lock(mu);
 259                 internal_dev_index = find_free_device_index(name, info, num_channels, address);
 260                 devices[internal_dev_index].address = address;
 261                 devices[internal_dev_index].name = name;
 262                 devices[internal_dev_index].info = info;
 263                 devices[internal_dev_index].num_channels = num_channels;
 264                 // Note: Purposefully does not overwrite held.
 265
 266                 display_name = devices[internal_dev_index].display_name();
 267         }
 268
 269         fprintf(stderr, "%s: Probed successfully.\n", address);
 270
 271         reset_device(internal_dev_index);  // Restarts it if it is held (ie., we just replaced a dead card).
 272
 273         DeviceSpec spec{InputSourceType::ALSA_INPUT, internal_dev_index};
 274         global_audio_mixer->set_display_name(spec, display_name);
 275         global_audio_mixer->trigger_state_changed_callback();
 276
 277         return ALSAPool::ProbeResult::SUCCESS;
 278 }
 279
 280 void ALSAPool::unplug_device(unsigned card_index, unsigned dev_index)
 281 {
 282         char address[256];
 283         snprintf(address, sizeof(address), "hw:%d,%d", card_index, dev_index);
 284         for (unsigned i = 0; i < devices.size(); ++i) {
 285                 if (devices[i].state != Device::State::EMPTY &&
 286                     devices[i].state != Device::State::DEAD &&
 287                     devices[i].address == address) {
 288                         free_card(i);
 289                 }
 290         }
 291 }
 292
 293 void ALSAPool::init()
 294 {
 295         inotify_thread = thread(&ALSAPool::inotify_thread_func, this);
 296         enumerate_devices();
 297 }
 298
 299 void ALSAPool::inotify_thread_func()
 300 {
 301         pthread_setname_np(pthread_self(), "ALSA_Hotplug");
 302
 303         int inotify_fd = inotify_init();
 304         if (inotify_fd == -1) {
 305                 perror("inotify_init()");
 306                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 307                 return;
 308         }
 309
 310         int watch_fd = inotify_add_watch(inotify_fd, "/dev/snd", IN_MOVE | IN_CREATE | IN_DELETE);
 311         if (watch_fd == -1) {
 312                 perror("inotify_add_watch()");
 313                 fprintf(stderr, "No hotplug of ALSA devices available.\n");
 314                 close(inotify_fd);
 315                 return;
 316         }
 317
 318         int size = sizeof(inotify_event) + NAME_MAX + 1;
 319         unique_ptr<char[]> buf(new char[size]);
 320         while (!should_quit) {
 321                 pollfd fds[2];
 322                 fds[0].fd = inotify_fd;
 323                 fds[0].events = POLLIN;
 324                 fds[0].revents = 0;
 325                 fds[1].fd = should_quit_fd;
 326                 fds[1].events = POLLIN;
 327                 fds[1].revents = 0;
 328
 329                 int ret = poll(fds, 2, -1);
 330                 if (ret == -1) {
 331                         if (errno == EINTR) {
 332                                 continue;
 333                         } else {
 334                                 perror("poll(inotify_fd)");
 335                                 return;
 336                         }
 337                 }
 338                 if (ret == 0) {
 339                         continue;
 340                 }
 341
 342                 if (fds[1].revents) break;  // should_quit_fd asserted.
 343
 344                 ret = read(inotify_fd, buf.get(), size);
 345                 if (ret == -1) {
 346                         if (errno == EINTR) {
 347                                 continue;
 348                         } else {
 349                                 perror("read(inotify_fd)");
 350                                 close(watch_fd);
 351                                 close(inotify_fd);
 352                                 return;
 353                         }
 354                 }
 355                 if (ret < int(sizeof(inotify_event))) {
 356                         fprintf(stderr, "inotify read unexpectedly returned %d, giving up hotplug of ALSA devices.\n",
 357                                 int(ret));
 358                         close(watch_fd);
 359                         close(inotify_fd);
 360                         return;
 361                 }
 362
 363                 for (int i = 0; i < ret; ) {
 364                         const inotify_event *event = reinterpret_cast<const inotify_event *>(&buf[i]);
 365                         i += sizeof(inotify_event) + event->len;
 366
 367                         if (event->mask & IN_Q_OVERFLOW) {
 368                                 fprintf(stderr, "WARNING: inotify overflowed, may lose ALSA hotplug events.\n");
 369                                 continue;
 370                         }
 371                         unsigned card, device;
 372                         char type;
 373                         if (sscanf(event->name, "pcmC%uD%u%c", &card, &device, &type) == 3 && type == 'c') {
 374                                 if (event->mask & (IN_MOVED_FROM | IN_DELETE)) {
 375                                         printf("Deleted capture device: Card %u, device %u\n", card, device);
 376                                         unplug_device(card, device);
 377                                 }
 378                                 if (event->mask & (IN_MOVED_TO | IN_CREATE)) {
 379                                         printf("Adding capture device: Card %u, device %u\n", card, device);
 380                                         probe_device_with_retry(card, device);
 381                                 }
 382                         }
 383                 }
 384         }
 385         close(watch_fd);
 386         close(inotify_fd);
 387         close(should_quit_fd);
 388 }
 389
 390 void ALSAPool::reset_device(unsigned index)
 391 {
 392         lock_guard<mutex> lock(mu);
 393         Device *device = &devices[index];
 394         if (device->state == Device::State::DEAD) {
 395                 // Not running, and should not be started.
 396                 return;
 397         }
 398         if (inputs[index] != nullptr) {
 399                 inputs[index]->stop_capture_thread();
 400         }
 401         if (!device->held) {
 402                 inputs[index].reset();
 403         } else {
 404                 // TODO: Put on a background thread instead of locking?
 405                 auto callback = bind(&AudioMixer::add_audio, global_audio_mixer, DeviceSpec{InputSourceType::ALSA_INPUT, index}, _1, _2, _3, _4, _5);
 406                 inputs[index].reset(new ALSAInput(device->address.c_str(), OUTPUT_FREQUENCY, device->num_channels, callback, this, index));
 407                 inputs[index]->start_capture_thread();
 408         }
 409         device->input = inputs[index].get();
 410 }
 411
 412 unsigned ALSAPool::get_capture_frequency(unsigned index)
 413 {
 414         lock_guard<mutex> lock(mu);
 415         assert(devices[index].held);
 416         if (devices[index].input)
 417                 return devices[index].input->get_sample_rate();
 418         else
 419                 return OUTPUT_FREQUENCY;
 420 }
 421
 422 ALSAPool::Device::State ALSAPool::get_card_state(unsigned index)
 423 {
 424         lock_guard<mutex> lock(mu);
 425         assert(devices[index].held);
 426         return devices[index].state;
 427 }
 428
 429 void ALSAPool::set_card_state(unsigned index, ALSAPool::Device::State state)
 430 {
 431         {
 432                 lock_guard<mutex> lock(mu);
 433                 devices[index].state = state;
 434         }
 435
 436         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 437         bool silence = (state != ALSAPool::Device::State::RUNNING);
 438         while (!global_audio_mixer->silence_card(spec, silence))
 439                 ;
 440         global_audio_mixer->trigger_state_changed_callback();
 441 }
 442
 443 unsigned ALSAPool::find_free_device_index(const string &name, const string &info, unsigned num_channels, const string &address)
 444 {
 445         // First try to find an exact match on a dead card.
 446         for (unsigned i = 0; i < devices.size(); ++i) {
 447                 if (devices[i].state == Device::State::DEAD &&
 448                     devices[i].address == address &&
 449                     devices[i].name == name &&
 450                     devices[i].info == info &&
 451                     devices[i].num_channels == num_channels) {
 452                         devices[i].state = Device::State::READY;
 453                         return i;
 454                 }
 455         }
 456
 457         // Then try to find a match on everything but the address
 458         // (probably that devices were plugged back in a different order).
 459         // If we have two cards that are equal, this might get them mixed up,
 460         // but we don't have anything better.
 461         for (unsigned i = 0; i < devices.size(); ++i) {
 462                 if (devices[i].state == Device::State::DEAD &&
 463                     devices[i].name == name &&
 464                     devices[i].info == info &&
 465                     devices[i].num_channels == num_channels) {
 466                         devices[i].state = Device::State::READY;
 467                         return i;
 468                 }
 469         }
 470
 471         // OK, so we didn't find a match; see if there are any empty slots.
 472         for (unsigned i = 0; i < devices.size(); ++i) {
 473                 if (devices[i].state == Device::State::EMPTY) {
 474                         devices[i].state = Device::State::READY;
 475                         devices[i].held = false;
 476                         return i;
 477                 }
 478         }
 479
 480         // Failing that, we just insert the new device at the end.
 481         Device new_dev;
 482         new_dev.state = Device::State::READY;
 483         new_dev.held = false;
 484         devices.push_back(new_dev);
 485         inputs.emplace_back(nullptr);
 486         return devices.size() - 1;
 487 }
 488
 489 unsigned ALSAPool::create_dead_card(const string &name, const string &info, unsigned num_channels)
 490 {
 491         lock_guard<mutex> lock(mu);
 492
 493         // See if there are any empty slots. If not, insert one at the end.
 494         vector<Device>::iterator free_device =
 495                 find_if(devices.begin(), devices.end(),
 496                         [](const Device &device) { return device.state == Device::State::EMPTY; });
 497         if (free_device == devices.end()) {
 498                 devices.push_back(Device());
 499                 inputs.emplace_back(nullptr);
 500                 free_device = devices.end() - 1;
 501         }
 502
 503         free_device->state = Device::State::DEAD;
 504         free_device->name = name;
 505         free_device->info = info;
 506         free_device->num_channels = num_channels;
 507         free_device->held = true;
 508
 509         return distance(devices.begin(), free_device);
 510 }
 511
 512 void ALSAPool::serialize_device(unsigned index, DeviceSpecProto *serialized)
 513 {
 514         lock_guard<mutex> lock(mu);
 515         assert(index < devices.size());
 516         assert(devices[index].held);
 517         serialized->set_type(DeviceSpecProto::ALSA_INPUT);
 518         serialized->set_index(index);
 519         serialized->set_display_name(devices[index].display_name());
 520         serialized->set_alsa_name(devices[index].name);
 521         serialized->set_alsa_info(devices[index].info);
 522         serialized->set_num_channels(devices[index].num_channels);
 523         serialized->set_address(devices[index].address);
 524 }
 525
 526 void ALSAPool::free_card(unsigned index)
 527 {
 528         DeviceSpec spec{InputSourceType::ALSA_INPUT, index};
 529         while (!global_audio_mixer->silence_card(spec, true))
 530                 ;
 531
 532         {
 533                 lock_guard<mutex> lock(mu);
 534                 if (devices[index].held) {
 535                         devices[index].state = Device::State::DEAD;
 536                 } else {
 537                         devices[index].state = Device::State::EMPTY;
 538                         inputs[index].reset();
 539                 }
 540                 while (!devices.empty() && devices.back().state == Device::State::EMPTY) {
 541                         devices.pop_back();
 542                         inputs.pop_back();
 543                 }
 544         }
 545
 546         global_audio_mixer->trigger_state_changed_callback();
 547 }